BORROWINGS (Details 2) - USD ($)		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015
Repurchase Agreement Counterparty [Line Items]
Repurchase Agreement Counterparties, Amount Outstanding		$ 804,811,000	$ 568,432,457
Repurchase Agreement Counterparties, Percent of total amount outstanding		100.00%	100.00%
Repurchase Agreement Counterparties, Weighted average days to maturity		16 days	26 days
Repurchase Agreement Counterparties, Market Value of collateral held		$ 876,121,505	$ 697,384,372
Merrill Lynch [Member]
Repurchase Agreement Counterparty [Line Items]
Repurchase Agreement Counterparties, Amount Outstanding			$ 99,770,000
Repurchase Agreement Counterparties, Percent of total amount outstanding			17.55%
Repurchase Agreement Counterparties, Weighted average days to maturity			30 days
Repurchase Agreement Counterparties, Market Value of collateral held			$ 154,005,234
Wells Fargo Securities [Member]
Repurchase Agreement Counterparty [Line Items]
Repurchase Agreement Counterparties, Amount Outstanding		$ 33,666,000	$ 32,192,000
Repurchase Agreement Counterparties, Percent of total amount outstanding		4.18%	5.66%
Repurchase Agreement Counterparties, Weighted average days to maturity		8 days	10 days
Repurchase Agreement Counterparties, Market Value of collateral held		$ 57,627,433	$ 53,711,547
Other North America [Member]
Repurchase Agreement Counterparty [Line Items]
Repurchase Agreement Counterparties, Amount Outstanding		$ 703,788,000	$ 291,806,000
Repurchase Agreement Counterparties, Percent of total amount outstanding		87.45%	51.34%
Repurchase Agreement Counterparties, Weighted average days to maturity		16 days	25 days
Repurchase Agreement Counterparties, Market Value of collateral held		$ 742,690,286	$ 315,040,818
Europe [Member]
Repurchase Agreement Counterparty [Line Items]
Repurchase Agreement Counterparties, Amount Outstanding	[1]	$ 4,624,000	$ 56,099,457
Repurchase Agreement Counterparties, Percent of total amount outstanding	[1]	0.57%	9.87%
Repurchase Agreement Counterparties, Weighted average days to maturity	[1]	44 days	46 days
Repurchase Agreement Counterparties, Market Value of collateral held	[1]	$ 9,605,308	$ 76,656,547
Asia [Member]
Repurchase Agreement Counterparty [Line Items]
Repurchase Agreement Counterparties, Amount Outstanding	[1]	$ 62,733,000	$ 88,565,000
Repurchase Agreement Counterparties, Percent of total amount outstanding	[1]	7.79%	15.58%
Repurchase Agreement Counterparties, Weighted average days to maturity	[1]	14 days	16 days
Repurchase Agreement Counterparties, Market Value of collateral held	[1]	$ 66,198,478	$ 97,970,226

[1] Counterparties domiciled in Europe and Asia, or their U.S. subsidiaries.